Israel has delayed an expected release of hundreds of Palestinian prisoners and detainees in exchange for returned Israeli hostages “until further notice,” the Palestinian Prisoners Society said early Sunday.

In what was set to be the largest swap under January’s ceasefire agreement, six hostages were freed, but the release of some 600 Palestinian prisoners was delayed. It comes after Shiri Bibas’s body was returned by Hamas.

Hamas on Saturday began to release all six remaining live Israeli hostages promised under the first stage of the ongoing cease-fire deal — as one heartbroken family finally received the remains of a mother murdered in terrorist captivity.